1. Field of the Invention
The present invention relates to a packaging container, and more particularly, to a packaging container using a pallet and enclosure box to package an article for storage and transport.
2. Discussion of the Background
Shipping containers are used to package large electronic equipment such as printers and photocopiers for storage and transport. A typical design of such containers includes an upper enclosure box to enclose an article therewithin, and a lower mounting platform or pallet having an open-sided hollow structure to accommodate tines of a forklift during handling of the container. The enclosure box is made of corrugated cardboard with the pallet formed of wood or plywood for strength and durability, although cardboard pallets are often used depending on specific applications.
FIG. 1 is an exploded perspective view schematically illustrating a conventional packaging container 1.
As shown in FIG. 1, the packaging container 1 includes a pallet 10 placed at the bottom; an enclosure base 11 bonded to the upper side of the pallet 10; an enclosure box 15 to enclose an article such as a printer, not shown, placed on the enclosure base 11; and a set of fasteners 17 for fastening the enclosure box 15 to the enclosure base 11.
In the packaging container 1, the pallet 10 comprises an open-sided hollow structure made of corrugated cardboard substantially rectangular in plan to support the entire enclosure thereon.
The enclosure base 11 comprises a folded sheet of corrugated cardboard, consisting of a substantially rectangular, center panel 12C; a first pair of opposed side flaps 12A each bored with two through-holes 14 for fastening with the fasteners 17, extending substantially vertically upward from a first pair of opposed, parallel edges 12a of the center panel 12C; and a second pair of opposed side flaps 12B for positioning the article being enclosed, extending substantially vertically upward from a second pair of opposed, parallel edges 12b of the center panel 12C.
The enclosure box 15 comprises an open-bottom box with a bottom side defining an opening to pass the article therethrough during placement onto the enclosure base 11, consisting of a top wall to cover the article from above, and four side walls to surround the article from all sides, two of which, on opposite sides, are bored with through-holes 16 to align with the through-holes 14 of the side flaps 12A when installed.
To assemble the packaging container 1, the pallet 10 is initially provided with the enclosure base 11 in a blank, unfolded state, attached to the upper surface of the pallet 10 with suitable adhesive. The enclosure base 11 is folded along the first pair of side edges 12a to raise the fastening flaps 12A substantially vertically upward, and along the second pair of side edges 12b to raise the positioning flaps 12B substantially vertically upward. After the enclosure base 11 is thus prepared, an article is mounted on the enclosure base 11 and provided with appropriate cushioning, such as expanded polystyrene foam pieces, followed by placing the enclosure box 15 from above onto the pallet 10 so that the article may pass through the bottom opening of the enclosure box 15 being installed. Assembly is completed by inserting the fasteners 17 into the through-holes 16 and 14 being aligned to each other, which fasten the enclosure box 15 to the enclosure base 16 by holding together their adjoining side walls.
In the packaging container 1 thus assembled, the entire dimensions of the enclosure base 11, including the center panel 12C as well as the side flaps 12A and 12B extending upward, are located within the enclosure box 15. This means the four side walls of the enclosure box 15 all rest on the upper surface of the pallet 10 and not on the center panel 12C of the enclosure base 11. To prevent the enclosure box 15 from accidentally slipping off the pallet 10, clearance C is provided between the adjoining edges of the enclosure box 15 and the pallet 10, which securely maintains the enclosure box 15 in position on the rectangular pallet 10 even when the container 1 is elevated, inclined, or impacted during transport and storage. Such provision of clearance, however, is an inefficient use of the limited area over the pallet 10, which would otherwise be used as part of the enclosure.
For optimizing space usage of the palletized container, a modified design has been proposed, in which the fastening flaps of the enclosure base are located outside the enclosure box, allowing for reduced clearance between the adjoining edges of the enclosure box and the pallet. FIGS. 2A and 2B are plan and partial side views, respectively, schematically illustrating such a modified packaging container 2.
As shown in FIGS. 2A and 2B, the general configuration of the packaging container 2 is similar to that depicted with reference to FIG. 1, including a cardboard pallet 20 placed at the bottom; a cardboard enclosure base 21 bonded to the upper side of the pallet 20; an enclosure box 25 to enclose an article such as a printer, not shown, placed on the enclosure base 21; and a set of fasteners, not shown, for fastening the enclosure box 25 to the enclosure base 21.
With additional reference to FIG. 3, which is a plan view schematically illustrating the enclosure base 21 in its blank, unfolded state, the enclosure base 21 used in the modified container 2 consists of a substantially rectangular, flat center panel 22C for attachment to the upper surface of the pallet 20; a pair of fastening flaps 22A provided with through-holes 24, extending from a first pair of opposed parallel side edges 22a of the center panel 22C; and a pair of positioning flaps 22B extending from a second pair of opposed parallel side edges 22b of the center panel 22C, all of which are integrally cut out of a single sheet of corrugated cardboard.
Assembly of the packaging container 2 is carried out in a manner similar to that depicted above, wherein the pallet 20 is initially provided with the enclosure base 21 folded along the first pair of side edges 22a to raise the fastening flaps 22A substantially vertically upward, and along the second pair of side edges 22b to raise the positioning flaps 22B substantially vertically upward, followed by mounting an article on the enclosure base 21, cushioning the article, placing the enclosure box 25 from above onto the pallet 20, and finally fastening the enclosure box 25 to the enclosure base 26 with the fasteners.
FIG. 4A is a partial perspective view schematically illustrating one corner of the packaging container 2 assembled, and FIG. 4B is an enlarged side view taken in the direction indicated by arrow A of FIG. 4A.
As shown in FIGS. 4A and 4B, the enclosure base 21 is sized and positioned with respect to the enclosure box 25 so as to position the fastening flaps 22A outside the enclosure box 25 and the positioning flaps 22B inside the enclosure box 25 when the container 2 is assembled. This means that in the assembled container 2, the side walls of the enclosure box 25 facing the fastening flaps 22A rest on the center panel 22C of the enclosure base 21, whereas those facing the positioning flaps 22B are left unseated slightly above the upper surface of the pallet 20. Compared to the conventional design depicted earlier, such a configuration allows the bottom edges of the enclosure box to be located closer to the outer edges of the pallet, which maximizes the area or space available for enclosing the article in the palletized container 2.
The modified packaging container 2, however, still has several drawbacks. One drawback is that the enclosure box 20, with its bottom edge not fully seated on the underlying surface, is susceptible to damage when subjected to loads.
With specific reference to FIG. 4B, the enclosure box 25 is shown with one side wall resting on the center panel 22C of the enclosure base 21 and another, adjoining side wall spaced away from the upper surface of the pallet 20 by a distance Δd corresponding to the thickness of the center panel 22C. When the packaging container 2 is under load, the spacing Δd between the bottom edge of the enclosure box 25 and the surface of the pallet 20 causes a concentrated stress that deforms or crushes the bottom edge of the enclosure box 25 around the corner of the enclosure box 25. The problem is particularly pronounced where the packaging container 2 is disposed under another container or several more containers, resulting in a reduced durability of the cardboard box which does not meet requirements for packaging large equipment for shipping.
Another drawback of the packaging container 2 is a considerable loss of material occurring in the production of the enclosure base 21. That is, forming the enclosure base 21 of a non-rectangular, complex polygonal blank cut out of a sheet of corrugated cardboard leaves remains 28 of the material where the adjacent edges of the side flaps 22A and 22B form a concave corner (see FIG. 3). Such remains 28 are typically disposed of as unusable material to be wasted, resulting in reduced cost and resource efficiency during manufacture of the packaging container.